Table 2. Fluorescent compounds used in spheroid uptake and elimination studies.

Fluorescent compound	Efflux transporter	Concentration (μM)	Solvent (maximum concentration)	Fluorescence wavelengths
Calcein AM	MRP2	10	DMSO (0.4%)	λ ex: 494 nm; λem 517 nm
Cholyl-lysyl-fluorescein	BSEP	5	Sterile dH2O	λ ex: 485 nm; λem 520 nm
2′,7′-Dichlorodihydrofluorescein diacetate	BSEP	10	DMSO (0.05%)	λ ex: 495 nm; λem 530 nm
Hoechst 33342	BCRP	10	Sterile dH2O	λ ex: 340 nm; λem 510 nm
Rhodamine 123	MDR1	10	DMSO (0.05%)	λ ex: 511 nm; λem 534 nm